The present invention relates to a folder with at least one cylinder equipped with at least one folding blade and holding devices taking the signatures at their front edge which cooperates with a respective cylinder provided with folding jaws, a guide mechanism located at each outlet wedge situated after the folding place in the direction of rotation of the respective cylinders cooperating in the folding process extending over the entire length of the cylinder which guides the parts of the sheets lying, after the folding place, on the circumferential section of the folding blade, and being taken therefrom in the folding process.
A folder of this design is commonly known. The guide mechanism illustrated only schematically usually consists of single-part tongues which are stationary and arranged next to each other. Experience has proven that these stationary tongues, in particular in their middle section, are subjected to rapid wear. The reason for this wear is that the halves of the sheets of the individual signatures which run ahead on the folding blade cylinder and, when the signatures are conveyed to the folding jaw cylinder, are jerkily accelerated opposite to their original direction of motion, due to this process strongly lash outwards and thereby always strike particularly hard against certain places of the middle section of the tongues forming the guide mechanism. The result is cavitation-like signs of wear in the form of hollows or break-offs respectively at the places struck. These local damages of the guide surface of the tongues forming the guide mechanism, which develop rapidly even after a relatively short period of use, may lead to damage of the signatures in the form of scratch marks, tears, smudged ink, etc., thus having an unfavorable effect on the quality of the final product. Therefore, it has been necessary heretofore to change the tongues at short maintenance intervals, which however results in high costs in maintenance and material and at the same time requires the machines to lie idle for quite a long time.